This document contains examples of calculating electromagnetic induction in coils and coupled inductors. It provides the formulas and steps to calculate: 1) The emf induced in a moving conductor in a magnetic field for different orientations. 2) The average emf induced in a coil when the current reversing over time causes the magnetic flux to change. 3) The mutual inductance and induced emf in two coupled coils when the current in one coil changes. 4) The self and mutual inductances, coupling coefficient, and equivalent inductance of coupled coils.

1. ELE101/102 Dept of E&E,MIT Manipal 1
Tutorial - Electromagnetic Induction
[1] A wire of length 1 m moves at right angles to its length at 60
m/sec in a uniform magnetic field of density 1 Tesla.
Calculate the emf induced in the conductor when the direction
of motion is (i) perpendicular to the field (ii) inclined at 300
to
the direction of the field (iii) parallel to field
[60 V, 30 V, 0 V]

2. ELE101/102 Dept of E&E,MIT Manipal 2
Tutorial - Electromagnetic Induction
[2] A coil of 1500 turns gives rise to a magnetic flux of 2.5 mWb
when carrying a certain current. If the current is reversed in
0.2 seconds, what is the average value of emf induced in the
coil?
[37.5 V]

3. ELE101/102 Dept of E&E,MIT Manipal 3
Tutorial – continued ….
[3] The self-inductance of a coil of 500 turns is 0.25 H. If 60% of
the flux is linked with a second coil of 1000 turns calculate
(i) the mutual inductance of the two coils. (ii) EMF induced in
the second coil when current in the first coil changes at the
rate of 100 A / Sec
(0.3H; 30V)

4. ELE101/102 Dept of E&E,MIT Manipal 4
Example
[4] Coil 1 of a pair of coupled coils has a continuous current
of 5A, and the corresponding fluxes φ1 and φ12 are
0.6mWb and 0.4 mWb respectively. If the turns are
N1=500 and N2=1500, find L1, L2, M and k.
Ans:
 L1 = N1 φ1 /I1= 0.06 H
 M = N2 φ12 /I1=0.12H
 k = φ12 / φ1 = 0.667
 L2 = 0.539H

5. ELE101/102 Dept of E&E,MIT Manipal 5
[5] Two coils with inductances in the ratio 1:4 have a
coupling coefficient k=0.6. When these coils are
connected in series aiding the equivalent inductance is
44.4mH. Find L1, L2, and M
Ans: L1 =6mH, L2 =24mH, M =7.2mH
Example

6. ELE101/102 Dept of E&E,MIT Manipal 6
Tutorial – continued ….
[7] Three magnetically coupled inductive coils having the following data
are connected in series as shown in Figure.
L1 = 12 H; L2 = 14 H; L3 = 14 H;
k12 = 0.33; k23 = 0.37; k31 = 0.65;
Find the equivalent inductance of the circuit.
ANS: 24.87 H

7. ELE101/102 Dept of E&E,MIT Manipal 7
Tutorial – continued ….
[8] Two inductances each of 10 and 29 H are connected in
parallel. If the current in 10 H changes at a uniform rate of 4
A in one second, what is the rate of change of current in 29
H inductance and in the entire network?
(1.3793 Amps/s and 5.3793 Amps/s)